Navigation systems and techniques are typically used to provide information indicative of position and/or movement. In one navigation system (also referred to here as a “personal navigation system”), the position and/or movement of a human is monitored using an inertial navigation system (INS) that is mounted to the human. In such a personal navigation system, corrective feedback is generated by a Kalman filter using a distance-traveled estimate generated using a motion classifier and/or a position estimate generated using one or more radio frequency (RF) navigation aids (for example, aids that employ global positioning system (GPS) technology). The corrective feedback is used to refine, for example, the processing performed by the INS and/or by the motion classifier. In particular, the use of RF navigation aids helps to reduce the growth of navigation errors. However, such RF navigation aids may not be available in all environments (for example, GPS receivers require an unobstructed view of the sky and are susceptible to jamming).